Apparatus employed in wireless telegraphy.



No. 627,650. Patented June 27, I899.

a. MARGONI.

APPARATUS EMPLOYED IN WIRELESS TELEGRAPHY.

(Application filed Jan. 5, 1899.) (No Model.)

r is a specification.

UNITED STATES PATENT Orrrcn.

GUGLIELMO MAROONI, OF LONDON, ENGLAND, ASSIGNOR TO THE WIRELESSTELEGRAPH AND SIGNAL COMPANY, LIMITED, OF SAME PLACE.

APPARATUS EMPLOYED IN WIRELESS TELEGRAPHY.

SPECIFICATION forming part of Letters Patent No. 627,650, dated June 27,1899.

Application filed January 5, 1899.

T0 at whom it nwty concern:

Be it known that I, GUGLIELMO MARco I, electrician, asubject of the Kingof Italy, residing at 28 Mark Lane, in the city of London, England, haveinvented certain new and useful Improvements in Apparatus Employed inWVireless Telegraphy, of which the following In the specification of aformer-patent granted to me, No. 586,193, I described a receiver inwhich the ends of an imperfect contact in a local circuit were connectedone to earth and the other to an insulated conductor.

According to this invention the conductor is no longer insulated, but isconnected to a capacity, which may be the earth, through the primary ofan induction-coil, while the ends of the imperfect contact are connectedto the ends of the secondary one of the connections, being through acondenser.

The induction-coil preferably consists of a few turns of insulated wire.Over or under this first winding, which constitutes the pri mary, iswound a secondary winding, which constitutes the'secondary. I

In order to obtain the best effects,it is essen-. tial that theinduction-coil should be of very thin wire. It is desirable that theprimary and secondariywindings ofthe coil should be close to each otherand that the windings of each should be in a single layer. It isdesirable that the induction-coil should be in tune or syntony with theelectrical oscillation transmitted, the most appropriate number of turnsand most appropriate thickness of wire varying with the length of waveof the oscillation transmitted.

The capacity of the condenser on the con-- nection between theimperfectcontact and the secondary of the coil shouldbe varied (in orderto obtain best effects) ifthelength of wave is varied. I H Y {W It isdesirable that the conductor connected should offer ,a large surface,and therefore the use of such materials as broad wire-netting in lieuofwire is desirable. I Itis also desirable to employ thick conductors ornetting orits equivalents at the transmitting end.

The introduction of the coil in the conductor Serial No. 701,251. (Nomodel.)

not only improves the signals, but also prevents to a great extent anyinterference due toatmospheric influences, as any atmosphericelectricity collected by the aerial conductor escapes to earth throughthe primary of the coil, thus preventing a charge from accumulating anddischarging itself through the imperfect contact. Any stray interferencecan be further minimized by substituting a suitable capacity for theearth.

I have used a condenserof about one-fourth microfarad capacity for theabove purpose.

Figure 1 is a diagram of the arrangement I prefer. Fig. 2 showsamodification. Fig. 3 shows the induction-coil.

In Fig. 1, A is a long conductor suspended in the air by insulators, andE. is a connection to earth or other suitable capacity. B is a localbattery, and His a relay working a signaling or other instrument. j isthe primary of the induction-coil or transformer,

which is inserted between A and E. It" is a an induction-coil ortransformer constructed as follows: The primaryj of the saidinduction-coil or transformer is wound on a glass tube j about .635centimeter in diameter. The said primary winding consists of twoparallel windings of two hundred turns each of copper wire .012centimeter in diameter insulated by a single covering of silk. Theresistance of these two windings in parallel is about 3.1 ohms. Thesecondary winding j of the induction-coil or transformer consists ofabout eight hundred turns of a similar but thinner wire .0O5 centimeterin di ameter wound over or under the primary winding. The resistance ofthe secondary windingis about one hundred and forty ohms.

The condenser 7t, which I preferably use, is composed of six tin-foil orcopper plates connected to each terminal, each plate being fivecentimeters by three centimeters, the plates beinginsulated byparaffined paper .017 centimeter thick.

lVhen using the above-described inductioncoil or transformer, I employas insulated conductor at each station a conductor formed of sevenstrands of about one-millimeter-diameter copper wire one hundred andforty feet long, the top of the conductor beingone hundred and twentyfeet from the ground. In some cases I use in lieu of the above-describedconductor a galvanized-iron netting about two feet broad and one hundredand thirty feet long, the top of the netting being about one hundred andten feet above the ground. In the latter case I obtain good results whenusing an induction-coil or transformer constituted as follows: secondarywinding of three hundred and seventy-five turns of copper wire .005centimeter in diameter insulated with one covering of silk, and wound ona glass tube .777 centimeter in diameter. Over this is wound the primarywinding of one hundred and seventy-five turns of a similar wire .012centimeter in diameter. The resistance of the primary winding is about7.1 ohms and that of the secondary about 79 ohins.

WVhat I claim is 1. In a receiver for electrical oscillations, thecombination of an imperfect electrical contact,-a local circuit throughit, an induction-coil, a capacity, a conductor connected to one end ofthe primary of the coil, a connection between the other end and thecapacity, connections between the ends of the imperfect contact and theends of the secondary of the coil and a condenser in one of the latterconnections.

2. In a receiver for electrical oscillations, the combination of animperfect electrical contact, a local circuit through it, a localbattery and relay included in the local circuit, choking-coilsrespectively included in said circuit between the terminals of theimporfeet electrical contact and the battery and relay, an indnotion-coil, a capacity, a conductor connected to one end of the primaryof the coil, a connection between the other end and the capacity,connections between the ends of the imperfect contact and the ends ofthe secondary of the coil, and a condenser in one of the latterconnections.

3. In a receiver for electrical oscillations, the combination of animperfect electrical contact, a local circuit through it, aninduction-coil, the primary and secondary of which consist of a singlelayer only, a capacity, a conductor connected to one end of the primaryof the coil, a connection between the other end and the capacity andconnections between the ends of the imperfect contact and the ends ofthe secondary of the coil.

4. In a receiver for electrical oscillations, the combination of animperfect electrical contact, a local circuit through it, aninduction-coil, the primary and secondary of which consist of a singlelayer only, a capacity, a conductor connected to one end of the primaryof the coil, a connection between the other end and the capacity andconnections between the ends of the imperfect contact, the ends of thesecondary of the coil and a condenser in one of the latter connections.

5. In a receiver for electrical oscillations, the combination of animperfect electrical contact, a local circuit through it, aninduction-coil, the primary and secondary of which consist of a singlelayer only, and in which the primary consists of a number of parallelwires connected at their ends, a capacity, a conductor connected to oneend of the primary of the coil, a connection between the other end andthe capacity and connections between the ends of the imperfect contactand the ends of the secondary of the coil.

6. In a receiver for electrical oscillations, the combination of animperfect electrical contact, a local circuit through it, aninduction-coil, the primary and secondary of which consist of a singlelayer only, and in which the primary consists of a number of parallelwires connected at their ends, a capacity, a conductor connected to oneend of the primary of the coil, a connection between the other end andthe capacity and connections between the ends of the imperfect contact,the ends of the secondary of the coil and a condenser in one of thelatter connections.

7. In a receiver for electrical oscillations, the combination of animperfect electrical contact, a local circuit through it, aninduction-coil, the primary and secondary of which are both of wire notexceeding one-fiftieth of a centimeter in diameter, a capacity, aconductor connected to ,one end of the primary of the coil, a connectionbetween the other end and the capacity and connections between the endsof the imperfect contact and the ends of the secondary of the coil.

8. In a receiver for electrical oscillations, the combination of animperfect electrical contact, a local circuit through it, aninduction-coil, the primary and secondary of which are both of wire notexceeding one-fiftieth of a centimeter in diameter, a capacity, aconductor connected to one end of the primary of the coil, a connectionbetween the other end and the capacity and connections between the endsof the imperfect contact, the ends of the secondary of the coil and acondenser in one of the latter connections.

GUGLIELMO MARCONI.

Witnesses:

ROBERT B. RANSFORD, JOHN H. WHITEHEAD.

